A semiconductor device and particularly, a field effect transistor having a junction structure of metal, oxide and semiconductor (MOS) using a wide band-gap semiconductor such as silicon carbide (MOSFET) is required to reduce power dissipation in terms of application to power electronics and energy saving of equipment on which such a semiconductor device is mounted. Such a semiconductor device is particularly required to reduce power dissipation (ON power dissipation) during a current-conducting state, specifically reduce ON resistance.
This may be achieved by reducing channel resistance. For reduction of channel resistance, channel mobility may be increased by increasing the quality of a junction of metal, insulator and wide band-gap semiconductor, by reducing a channel length, or by increasing a channel width density, for example.
According to the disclosure of Japanese Patent Application Laid-Open No. 9-55506, a cell that conventionally has a linear stripe shape is shaped into a stripe with circular or rounded portions formed at opposite ends of a linear part, specifically the cell has a dumb-bell shape. Such cells are arranged in an offset pattern, thereby achieving a 25 to 35 percent reduction of ON resistance.